1. Field of the Invention
This invention relates in general to a method and apparatus for conveying sheetlike material, such as textile fabrics, and in particular to an apparatus for conveying and tensioning lengths of fabric for the purpose of hand dyeing and painting.
2. Description of Related and Prior Art
In the field of hand dyed fabrics, free flowing dyes are applied by hand, with brushes, primarily to cotton and silk, in various original patterns. Although the dyes may be thickened, in the preferred technique, a characteristic "watercolor" look is desirable. This requires special handling of the fabric. The material must be horizontal, so the flow of the dye on the surface is regular and controllable. If the fabric to be dyed is laid loosely on a worktable, the applied dye will run along the irregularities and folds created by the loose fabric. The solution is to keep a length of material under constant tension as dye is applied.
In art forms such as oil painting, pigments are applied to an impermeable surface such as primed canvas, and the back of the canvas remains dry. When dye is applied to a material, the liquid permeates the fabric, so if it touches any object when wet, the dye will transfer through the fabric to the object. This produces a noticeable defect called "mark off", which spoils the design. The solution is to suspend the fabric above the work surface while the fabric is moving, and to dry it continuously as it travels, so it is dry before it again touches any surface.
The current method for hand dyers who must hand dye bolts of material of typically fifty yards is to unwind a piece of the fabric of the length of a work table, typically from eight to twenty feet, and then pin it to a frame with push pins to hold it off the surface. The dyer paints the section, and must wait until the piece is dry to unpin it, fold the painted section, and laboriously repeat the process for the next length. In addition to the time lost waiting for the piece to dry, the length of fabric is unwieldy, and subject to mark off. Another problem that results is that the material slackens and subsequently drops after being wetted with the dye, so the center of the fabric touches the work table, causing "mark off". The push pins must then be re-positioned, which is inconvienent.
Another problem with push pins is that the heads of the pins extend above the surface of the fabric, hindering the free movement of the brush as it passes over them. If the brush touches a push pin, the dye can accumulate at the point where the brush touches the pin, and the excess dye must be blotted quickly by the dyer to avoid spoiling the design. Another problem is that dye tends to collect on the under surface of the push pins from the wet fabric, causing "mark off", which necessitates cleaning the pin after every piece dyed.
The present invention solves these problems by offering an apparatus which allows the hand dyer to continuously dye a bolt of material from end to end. The fabric, in bolt form on a cardboard tube, is slipped onto a free wheeling supply roll, threaded through an adjustable tension apparatus, past an idler roller which turns the fabric to the horizontal position, past the dyeing area to a drying apparatus, an then onto a cardboard tube fitted over the drive roller, which is powered by a conveyor drive motor controlled by an electronic speed control. The drive roller is fitted with a hinged, sharpened, serrated, drive knife, which is held in contact with the inside of the removable cardboard tube by a leaf spring. The drive roller sits with one end removably seated in a notched bearing, while the opposite end is fitted with a universal joint, so the roller swivels off the notched bearing and the tube with the fabric is easily removed. If subsequent operations such as adding resists or dyeing areas with additional color are necessary, the fabric is slipped off the drive roll, replaced on the supply roll, and the additional processes are easily accomplished. This method and apparatus has been in use in my workshop since February, 1990, and has improved the production of hand dyed material in my workshop by a factor of five over the previous method of pinning short lengths of material to a frame off the work surface.